Strengthening of concrete members using fiber reinforced plastic (FRP) has emerged as a viable technique to retrofit/repair deteriorated infrastructure. In this study, the flexural performance of concrete beams strengthened with FRP plates has been investigated by means of a Finite Element analysis. The work reported in this thesis deals with the analytical models, proposed to predict the behavior of concrete members strengthened with externally bonded FRP plates, including normal concrete and reactive powder concrete (RPC). The surface – based cohesive behavior is also captured to represent the interfacial bonding between concrete and FRP. The results of the numerical simulations are used to confirm the experimental results in previous researches. The numerical results show an excellent agreement with the measured data.